Electrophysiology catheters are commonly-used for mapping electrical activity in the heart. Various electrode designs are known for different purposes. In particular, catheters having basket-shaped electrode arrays are known and described, for example, in U.S. Pat. Nos. 5,772,590, 6,748,255 and 6,973,340, the entire disclosures of each of which are incorporated herein by reference.
Basket catheters typically have an elongated catheter body and a basket-shaped electrode assembly mounted at the distal end of the catheter body. The basket assembly has proximal and distal ends and comprises a plurality of spines connected at their proximal and distal ends. Each spine comprises at least one electrode. The basket assembly has an expanded arrangement wherein the spines bow radially outwardly and a collapsed arrangement wherein the spines are arranged generally along the axis of the catheter body.
It is desirable that a basket assembly be capable of detecting in as few beats as possible, including a single beat, as much of the electrical function of the region in which the electrode assembly is deployed, such as the left or right atrium as possible. By implementing a greater number of electrodes in the electrode assembly, correspondingly greater and more complete coverage of the region may be obtained. Further, the increased number of electrodes may reduce or eliminate the need to reposition the electrode assembly to access all of the desired area in the region. Often, increasing the number of electrodes corresponds with an increase in the number of spines or other structures that support the electrodes. These spines are joined at a distal end by a central hub. As the device is deployed, a number of the distal electrodes may be put in a position that they are not in contact with the tissue. Additionally, the increase in the number of spines generally relates to an increase in the length and diameter of an elongated distal hub that is used to connect the spines. Devices that have a larger distal hub may be harder to deliver and deploy within a patient and may increase the risk of trauma to the tissue. Another problem with prior art distal hubs is that the movement from a delivery state to a deployed state causes stress in the structure as it transitions. This stress may cause undesirable damage to the device. As such, there is a need for a basket-shaped electrode assembly having an increased electrode density while maintaining a sufficiently minimized distal hub diameter and length that will improve the deployment and electrode contact within a chamber of a patient's heart and decrease the stress to the material as the device transitions to the deployed configuration. The techniques of this disclosure satisfy this and other needs as described in the following materials.